I have a problem.
I'm using the Mac version. On whatever map, when I start to build I crash. I can place a few bricks of any size or type slowly. But if I hold down enter to place the bricks and make lots of them (say, with super shift) it'll suddenly crash. The screen freezes, with newly placed bricks still partially highlighted, then the game quits. This persistently happens in single player, but hasn't happened online.